The Arduino MKR MEM shield will allow you to add more flash memory and storage. It provides 2-megabytes of flash memory. It also includes a slot for adding a microSD card to store several gigabytes...
The MKR Proto Shield is a prototyping shield designed for your MKR board. This shield easily plugs onto your MKR using its provided female/male headers, and offers a duplicate breakout for each pin...
The MKR Relay Protoshield allows you to easily add relays to your MKR board based project. The shield provides two relays (Datasheet) called RELAY1 and RELAY2 commanded by pin 1 and pin 2 respectiv...